IP Multi-Media Subsystem (IMS) defined by the 3GPP and 3GPP2 standards open the door to a whole new range of new multi-media technologies, such as Voice over IP (VoIP) and IPTV. The IMS service architecture enables to combine services of various platforms to combined services. These combined services make use of the functionalities of various platforms to which end-terminals are connected to and are also referred to as blended or composite services.
WO2007/070652 describes an example of a blended or combined service allowing the caller ID information of the calling party to be displayed on the TV system of a subscriber. This caller ID service is implemented in the standard IMS services architecture. Interaction between the telephone and television services is managed by means of a central service broker referred to in IMS as the “Service Capability and Interaction Manger” (SCIM). The SCIM is implemented in the session control layer between the application server layer and the transport and end point layer as defined in the IMS architecture.
The service broker will receive incoming requests of services and processes these requests on the basis of a predetermined scheme such as first come first serve, priority or another predetermined sequence. Such schemes are known from service interactions in Intelligent Networks (IN), IMS, Parlay, etc. The service broker functions as a central gateway and thus requires all information traffic from and to the services to be led via the service broker. Such centralized scheme has disadvantages.
A first problem relates to the scalability of a central system. Increasing the number of services and combined services greatly increases the complexity of the central service manager. Further, increasing the number of end-terminals will greatly increase the data traffic to be controlled. The central service manager will become a bottleneck in scaling the system to large-scale applications.
A second problem relates to the fact that addition of a new service to an existing service system managed by a central broker will require to configuration and adaptation of the central broker. Frequent adaptation of the central broker bears the risk of a major failure of the whole service delivery.